Service Insertion Architecture (SIA) provides a platform independent framework for inserting services into a network. A service may be regarded as an application that operates at one or more layers of the Open System Interconnect (OSI) networking stack. For example, a service may be an application that operates at one or more of, layers three (L3) (Network) through seven (L7) (Application). A service may be considered to be an optional function performed on a network that provides some value to a network user. Services may include, for example, encryption, decryption, special routing, intrusion management, and accounting. A service may be distributed throughout members of a service path. The members may be referred to as service nodes.
SIA includes a control plane entity that is known as a service broker (SB). Services register with a service broker and thus a service broker can provide a consistent domain-wide service view. A service may be implemented as a service path. A service path may be organized as an ordered list of segments, where a segment represents a service feature provided by a service node. A service broker can, therefore, instantiate service paths when service nodes are registered. A consumer of a service may be referred to as a service classifier (SCL). A service broker can allocate a service path to a consumer when the consumer registers with the broker. A service broker may also distribute information concerning service path segments to service nodes and to consumers to facilitate setting up the data plane for the SIA.